Four proteins of a peripheral and central nervous system have been targeted for study -- the myelin basic protein, proteolipid, myelin associated glycoprotein, and cyclic nucleotide phosphohydrolase. The first phase of the molecular level studies is the cloning of the genes coding for these proteins. To this end, we have obtained the necessary human perinatal brain tissue, prepared cDNA libraries from brain mRNAs, and have searched among the five million library clones in order to identify those which contain the genes for myelin basic proteins. We have positively identified several clones of each protein and are characterizing them extensively.